Replaceable multiple unit fuse plug



Dec. 25, 1951 w. T. STANLEY REPLACEABLE MULTIPLE UNIT FUSE PLUG Filed Jan. 5 195l III-l BWWQm QTrOQA/CY Patented Dec. 25, 1951 UNITED STATES PATENT F F I CE REPLACEABLE' MULTIPLE UNIT FUSE-PLUG William 1. Stanley, Indianapolis, Ind. Application January 5, 1951, Serial No. 204,509 Claims (01. ace-12's) This invention relates to a screw type fuse plug wherein a replaceable fuse element in-mul tiple form may be replaced. A- primary object of the inventionre'sides in the fact that the structure may beconstructed to occupy substantially the same space as-that'of thepresent, single fusewhich may berelatively low in cost so that in the long run, over'a period of time, there will be" afiected a considerable saving. in costover and above the heretofore practice 01E having to buyseparate single fuse units.

These and many other objects andadvantages ofthe invention will-become'apparent to those versed-in the art in the'following description of one embodiment asillus'trated'in the accompanying drawin'glin which Fig. Li's-a view inside elevation in partiaI'seotion of a structureembodying the invention; Fig; 2 is'a top plan view of the structure;

Fig. 3' is a view in section on the line 3'-3 i Figi-Zg Fig. 4 is a view in bottom plan ofthe inse unit;

Fig. 5 is a-- view insideelevation of the fuse unit;

Fig. 6 isa-v'iew in top planof the fuse unit; and

Fig. 7 is a view in transverse section on-the line !1 in Fig. 6, with the fuse material removed? The views in the-drawing are 'on' a's'cal'e of approximately twice actual size or the device ein-'-' bodying the invention;

A base 10 is formed to have the low'ei portion shaped in the usual manner to receive therearound a conducting ferrule H having screw: threads I2 which will engage in the usual-fuse receptacle (not shown) Thebody" 10' ismade outof any suitable-insulating matenar such as porcelain, the material being not of the essence of the -invention-,- but being necessarily a g ooddi-' electric The" upper-- portionof theb'o'dy 10' flares out war'dly 'i'nto' ahead portion l 3*whichis essentially a cup having a lower floorth'ei'ein designated by" the numeral l 4;

Along the side of the body l0 extending up'inside of the ferrule l I; is a conductor I5" which has its upper end [(5 passed' through-the floor I 4- and turned inwardlythereovera distance" to,"

2 wards the axisof the body 10. The conductor I5 is maintained in an electrical contact with the fer-rule H. g

Axially extending throughthe body 10 in more or less fixed positionthereinisa post I! having an external contact head l8 across the lower end of the body l0 spaced in an insulating manner from the lower end-of the ferrule II. This post ll extendsup through the body ID to receive screwthreadedly on a portion thereof a nut l9 which bears compressibly against the floor 20 formed-in a counterbore 2i in the floor M. From thenut- 19, the post I! extends in a continuing and axial manner upwardly therefrom by a reduced diameter end 22. V

A fuse carrier 23 is formed in acircular manner to be essentially adisk, and has an external diameter less than the internal diameter of the cup l'3.- This carrier 23 ismade out of any suitabledielectric-material, a ceramic material being suitable, although any of the electrically insulatingr plastics may be employed.

Inthepresent showing, there is provision made for six fuse operative elements which will hereinafter be described. To accommodate these individual elements, the carrier 23 is formed into six general compartments on the top side designated bythe numerals 24-29 inclusive. These compartments each are open from the top side, and are defined by intervening vertically disposed partitions 69 which extend radially inwardly toward the axis to open into a central passageway extending entirely through the carrier 23. In other wordsthese Various walls BSextend vertically downwardly from their individual compartments to form vertically disposed ribs 3| within the passageway 30. The underside of the carrier 23,'Fig. '7, is provided withan upwardly extending counterbore 32 so as to leave an annular flange 33 around the marginal portion of the'carrier 23 to extend downwardly.

The top sideofthecarrier 23 is bounded by an upturnedfiange- 34 which forms the outer wall of each of the various compartments 24-29. The top edge of this flange 341s in the-same plane as'thetop edges 'of 'the various walls'69. Between each adjacent pair of walls 69, the flange 34 is notched as at 35', centrally between the outer ends of -the walls 69.

A fuse spider generally designated by the numeral 3B is' formed to have a'ce'ntral cup-shaped thin'ible 31 to have a bottom annular plate 38 fromwhich extend upwardly six legs 39, equally spaced around-the peripheral portion of the plate 38'. The cup-37 is pressed downwardly through the-passageway 38 to have the plate 38 disposed at-a'distance below the underside of the carrier 23;:Fig. 5; This-entrance of thecup 31 through the passag'eway-tu ismade possible-by reason of each individual leg 39 being formed of a width which will permit it to enter between the extending ends of the walls 69 in that passage 30.

Each leg 39 is bent over the corner 40 of the carrier 23 at the inner end of each compartment 24-29 and the leg 39 is carried across the respective compartments to pass through the notches 35 and then be carried downwardly on the outside of the carrier 23 to terminate by an inturned That portion of each leg 39 which traverses the compartment in each instance, being cen-' tered radially of that compartment in respect to the axis of the carrier 23, is provided with a neck 4| which is made to have that cross section to give the desired rated amperage load limit.- That is the neck 4| is so proportioned that the leg 39 will melt across that portion when there is an overload beyond the rated capacity.

As will be noted particularly in Fig. 3, that portion of the leg 39 which traverses across each compartment 24 is inclined upwardly from the corner or edge 49 to the notch 35 so that it is removed from contact with the floor of the-compartment in each instance. Also the leg 39 in traversing the compartment has its plane generally below the plane of the top edge of the flange 34 since the legs pass through the notches 35 to so dispose the legs 39. The assembly of the fuse spider 31 with the carrier 23 as has just been described forms a unit which is then pressed frictionally into a bore 45 on the underside of a cap 46. The external diameterof this cap 46 is such that it will fit revolubly within the cup 3. The leg portions 41 which carry across the flange 33 are presented in the path of the overturned end 16 of the conductor l5 when the cap 46 is mounted within the cup [3, Fig. 3. This mounting of the cap 46 is achieved by providing the underside of the cap 46 with a downwardly extending well 48 which extends freely with clearance into the spider 31 out of contact with the upturned legs 39. The post upper part 22 extends through the bottom of this cup 48 and upwardly beyond the top side of the cap 46 to receive a button 49 screw-threadedly thereon.v Between the underside of the button 49 and the bottom of the cup 48 is placed a compression spring 50 so that the cap 46 is yieldingly main-- tained within the cup |3. j

Preferably there is a washer or suitable bearing plate 5| placed on top of the nut l9, and against which bearing plate 5| the fuse element'plate 38 may ride. The plate 5| is made out of a conducting material so that there is electrical conduction between the plate 38 through the plate 5| to the post I1 and consequently the exposed head IS.

The cap 46 is provided with some means for enabling. an operator to revolve it within the cup i3, such means herein being shown as two upwardly extending lugs 52 and 58.

The overturned end I6 of limited circumferential length, preferably being approximately the same as the width of the leg 39 where it comes into contact therewith. This is indicated in Fig. 5 where the conductor I5 is fragmentarily shown, with the end IS in contact with the leg 39.

Around the outer portion of the fioor l4 there is ranged in regular order a number of upwardly extending lugs 53 there being six such lugs required where there are six of the legs 39. These lugs 53 have recesses 54, Fig. 1, appearing there-.

between, one side of which recess is formed by a vertically disposed wall 55, and the other side by an inclined wall 56.

The underside of the cap 46 is provided with a number of downwardly extending posts 51, Fig. 2, herein shown as three in number. Each of these posts 51 is formed to fit between the adjacent lugs 53 within the recess 54. By reason of the 'fact that the vertical wall 55 is presented at the side of the recess 54, the post 51 cannot be turned in a counterclockwise direction as viewed in the various figures in the drawing. However since there is the inclined floor 56 presented on the other side, the leg 51 may travel thereup as the cap 46 is turned in a clockwise direction, this travel being against the pressure of the restrain ing spring 50 so that in order to permit the post 51 to come up out of the recess 54 and ride on the top of the lug 53, the-cap 46 will have to lift itself from the floor l4 against the resistance of the spring 59. This means that as the cap 46 is turned, the under areas 41 of the v.legs 39 will likewise be lifted to be out of the path of the overturned end |6 as the area 41 is carried thereaway, and the next area is brought thereto. In other words the area 41 is not so presented as to be liable to catch on the side edge of the overturned end l6, but is lifted and placed down thereon in a compressive manner as the areas 41 may be advanced one after another to come into contact with that end portion I6.

Thus it is to be seen that in the stationary position, Fig. 3, the spring 50 serves not only to seat the fuse spider plate 38 intimately on the conductor plate 5|, but it also serves to bring the leg 39 and the area 41 into compressive contact with the other conductor l6, the legin eifect being compressed between that portion l6 and the underside of the cap 46.

The retaining button 49 is located between the upwardly extending members 52 and 58 in such a manner that it may be tightened or loosened therebetween as may be required. Preferably the cap 46 is made out of a transparent material as indicated in Fig. 2, so that the legs 39 may be viewed therethrough, whereby the condition of the leg in each of the compartments 24-29 may be determined by visual inspection. On oneside of the top edge of the cup |3 there is provided an indicator 59, so positioned that whenever a post 51 is within a recess 54, there will be a fuse leg 39 directed theretoward. In other words the fuse leg 39 will be in that position always when the area 41 is in contact with the conductor end l6. 7 It is known that when the fuse leg 39 may melt under an overload, that there is in effect a slight explosive result forming gases, and the chambers 24-29 are provided to take care of that contingency,, together with the opening down through the passageway 39 which is maintained around the cup 48 entering therein, the legs 39 being separated one from the other as they leave the spider plate 38 to have the openings 60 to permit the gases to travel therethrough into the much larger chamber 6| provided on the outside of that fuse element cup 31, Fig. 3. In other words the explosive efiect is exerteddownwardly through the passageway 39 so that the top face or rather the entire underside of the cap 46 is kept clean in order to permit inspection of the individual legs 39. I

Moreover there is no danger of the metal melt- 24-29.,coming into contact, with. the metalin an,-

other compartment which would tend to vary the overload rating should that occur. The top edges ofthe partitions 69 are in substantial contact with the underside of the cap 46 so that there is not much tendency of the gases to be transmitted from one compartment to the other thereover. By: the time the. gases have;- entered the. passageway 30, the pressures have; been so dissipated or lowered that there is no likelihood of the explosiveeffect in any one compartment having any effect in an adjacent compartment from the entry way provided between the vertical edges 3| of these partitions 29.

Therefore it is to be seen that I have provided a very unique, yet highly serviceable, eificient, and low cost construction. While I have shown the invention in the one embodiment, it is obvious that structural variations may be employed without departing from the spirit of the invention, and I therefore do not desire to be limited to that precise form beyond the limitations which may be imposed by the following claims.

I claim:

1. A multiple unit fuse plug comprising a body having an open cupped end with a floor from which a counterbore extends into the body; a central conducting post carried by the body extending axially through said counterbore and said cupped end; a conductor positioned on the floor of said end at a distance from the axis of 1 said post; a cap revolubly carried in said cupped end and having a counterbore entering its under side; a fuse carrier having an external diameter to permit entrance into said cap counterbore; said carrier having a central opening therethrough and being provided with a plurality of compartments on its upper side defined by side partition walls extending radially of the axis of the carrier; a fuse element comprising a central plate, a

plurality of legs radiating from the plate and ext tending approximately normal thereto to define a cup extending through said central opening to present said plate downwardly of said carrier, said legs each extending from said central opening radially outwardly across one of said compartments, downwardly from the outer side of the compartment and thence around inwardly on the underside of the carrier to present a contacting area thereunder adjacent the margin thereof;

said areas being located in spaced relation circumferentially of the carrier at substantially the same radial distance from said axis as is said conductor.

2. A multiple unit fuse plug comprising a body having an open cupped end with a floor from which a counterbore extends into the body; a central conducting post carried by the body extending axially through said counterbore and said cupped end; a conductor positioned on the floor of said end at a distance from the axis of said post; a cap revolubly carried in said cupped end and having a counterbore entering its under side; a fuse carrier having an external diameter to permit entrance into said cap counterbore; said carrier having a central opening therethrough and being provided with a plurality of compartments on its upper side defined by side partition walls extending radially of the axis of the carrier; a fuse element comprising a central plate, a plurality of legs radiating from the plate and extending approximately normal thereto to define a cup extending through said central opening to present said plate downwardly of said carrier, said legs each extending from said central opening radially outwardly across one of said compartments," "downwardly 'from the. outerside of the compartment and thence around; inwardly on the underside of the carrier to present a contacting area thereunder adjacent the margin thereof said areas being located in spaced relation circumferentially of the. carrier atsubstantially the same radial distance from said axis as is said conductor; said post having an inner abutment thereon against which said plate may contact; an outer abutment on said post; and a spring between said outer abutment and said cap simultaneously-urgingone of said areas in contact with said conductor, and said plate into contact with said inner abutment to provide a circuit between the post through said leg to said conductor.

3. A multiple unit fuse plug comprising a body having an open cupped end with a floor from which a counterbore extends into the body; a central conducting post carried by the body extending axially through said counterbore and said cupped end; a conductor positioned on the floor of said end at a distance from the axis of said post; a cap revolubly carried in said cupped end and having a counterbore entering its under side; a fuse carrier having an external diameter to permit entrance into said cap counterbore; said carrier having a central opening there through and being provided with a plurality of compartments on its upper side defined by side partition walls extending radially of the axis of the carrier; a fuse element comprising a central plate, a plurality of legs radiating from the plate and extending approximately normal thereto to define a cup extending through said central opening to present said plate downwardly of said carrier, said legs each extending from said central opening radially outwardly across one of said compartments, downwardly from the outer side of the compartment and thence around inwardly on the underside of the carrier to present a contacting area thereunder adjacent the margin thereof; said areas being located in spaced relation circumferentially of the carrier at substantially the same radial distance from said axis as is said conductor; said post having an inner abutment thereon against which said plate may contact; an outer abutment on said post; and a spring between said outer abutment and said cap simultaneously urging one of said areas in contact with said conductor, and said plate into contact with said inner abutment to provide a circuit between the post through said leg to said conductor; and means spacing said areas from said conductor during turning of said cap.

4. In a multiple fuse unit, a fuse element comprising an insulating body generally disc-like in shape having upturned and downturned annular flanges around its periphery; said body having a central hole therethrough; a plurality of partition walls extending radially from said hole to said upturned flange to define compartments therebetween; a fuse member comprising a central contacting plate, a plurality of legs radiating and turned upwardly from the plate to define a thimble extending through said body hole; each of said legs extending laterally across the body from the hole across one of said compartments, across said upturned flange, downwardly, and back under said downturned flange, and upward- 1y inside thereof by a terminal end to present a contact area under that flange.

5. In a multiple fuse unit, a fuse element comprising an insulating body generally disc-like in shape having upturned'and downturned annular flanges around its periphery; said body having a central hole therethrough; a plurality of partition walls extending radially from said hole to said upturned flange to define compartments therebetween; a fuse member comprising a central contacting plate, a plurality of legs radiating and turned upwardly 'from the plate to define a thimble extending through said body hole; each of said legs extending laterally across the body from the hole across one of said compartments,'across said upturned flange, downwardly,

and back under said downturned flange, and up wardly inside thereof by a terminal end to present a contact area under that flange; said upturned flange being notched at each of said compartments to receive said legs through the notches, the notches serving to space the legs circumferentially of the flange, and to space the legs above the top face of the body.

WILLIAM T. STANLEY.

No references cited. 

